This invention relates generally to a machine for severing standing crops from the ground to initiate a harvesting process and, more particularly, to a mower conditioner incorporating a rotary disc cutterbar having a preselected number of transversely oriented cutter modules having rotatable discs supported thereon and carrying knives to sever standing crop by an impact action and convey the severed crop to a conditioning mechanism before being discharged to the ground.
Disc cutterbars have been utilized in agricultural harvesting implements for many years. Each disc cutterbar includes a plurality of transversely spaced disc cutters driven for rotation about a generally vertical axis. Each disc cutter has two or three knives pivotally mounted on the periphery thereof to sever standing crop from the ground through an impact action. For background information on the structure and operation of disc cutterbars, reference is made to U.S. Pat. No. 4,815,262, issued to E. E. Koch and F. F. Voler, the descriptive portions thereof being incorporated herein by reference.
The construction of disc cutterbars has evolved over the years to the configuration of having a modular construction with cutter modules and spacer modules, such as shown in U.S. Pat. No. 4,840,019, issued to L. J. Pingry, the descriptive portions of which are incorporated herein by reference. In some instances, the cutter modules and the spacer modules were integrally formed into one unit such as shown and described in U.S. Pat. No. 4,947,629, issued to R. Ermacora and H. Neuerburg.
It has been found that the specific use of the disc cutterbar apparatus, e.g. whether used as part of a disc mower, such as shown and depicted in U.S. Pat. No. 4,955,187, issued to C. van der Lely, which is typically supported at one end, or as part of a disc mower-conditioner which usually provides support to the cutterbar at both opposing ends thereof, carries with that particular use a different set of design parameters than other machines in which the cutterbar is utilized.
For example, the load imparted stresses relative to the spacer segments or modules on a disc mower cutterbar are different that the corresponding stresses on a disc mower-conditioner cutterbar. The tensile loads on the cutterbar are highest at the rear and center when used in a disc mower-conditioner, but at the front and inboard tractor end of the cutterbar when utilized in a disc mower.
A modular disc cutterbar of the type shown in the aforementioned Pingry patent is made up of segments comprising drive modules and spacer modules which can be joined at flange faces with retention mechanisms like threaded fasteners. The cutterbar spacer modules which are used to space and support the drive modules need to be sized to carry the highest loads. Because of the need to keep spacer modules with a uniform size and configuration no matter where the location the spacer is used along the transverse length of the cutterbar, the same spacer configuration is used along the full length of the cutterbar, resulting in some spacer modules being lightly loaded and constructed stronger and heavier than is structurally needed.
The weight of the completed disc mower assembly on a disc mower-conditioner needs to be as light as possible to minimize the required size of the cutterbar flotation springs and to reduce the inertia forces imposed on the cutterbar components when the cutterbar strikes and slides over an obstacle at high ground speeds. The weight of the cutterbar when utilized in a disc mower configuration also needs to be as light as possible to minimize the force and friction from the ground to minimize the wear of the ground contacting skid shoes, and also to minimize the damage to the crop which comes in contact with the skid shoes. A further consideration in keeping the weight of the cutterbar as light as possible is to reduce the loads imposed on the frame components when the disc mower is placed into a transport position in which the total weight of the cutterbar is supported by the frame. A corollary consideration is the desire to keep these frame components as light as possible.
The disc cutterbar when used in a disc mower conditioner is supported near its ends with the center of the cutterbar underneath the conditioning rolls being unsupported. During operation in the field, the ground forces are exerted upward onto the cutterbar skid shoes. These forces deflect the cutterbar upward, particularly if the cutterbar is being operated on a ridge near the center of the cutterbar. This deflection of the center of the cutterbar causes the cutterbar support arms to also deflect. The rise of the mid-span of the cutterbar causes the cutterbar to bow and to twist the support arms. A rigid fixation of the support arms onto the disc mower conditioner header can result in cracking of the header side sheets.
It is important to maintain the cutterbar in a nearly precise vertical position relative to the header. Too much vertical motion of the cutterbar due to radial clearance at the cutterbar arm support joints will allow the cutterbar knives to strike the lower conditioning roll and cause the cutterbar drive joint to slide on its drive shaft, which can cause the shaft and joint hub to wear and/or apply a thrust load on the drive shaft as the cutterbar raises and lowers relative to the header while the drive is transmitting power.
When cutting long viney crops with a disc mower conditioner, a device is needed to guide the vines into the cutterbar knives so that the vines are cut rather than caught and pulled by the conditioning rolls. The vines that cause the most problem are growing laterally to the header. If the vines are not cut, but instead are pulled by the conditioning rolls, the power to the rolls increases significantly. The tractor engine RPM drops and the torque on the driveline components increases, and the rolls' lugs wear. In addition, the vines can wrap on the rolls if the vines are not cut.
Trailed implements, such as disc mower conditioners, with lift systems that are positioned with one or more hydraulic cylinders require a device to positively lock the implement in the raised position to insure that during transport on the highway the implement will not lower due to a hydraulic leak or failure. A mechanism is needed to permit the operator to engage a lever before getting onto the tractor that will engage the locking device automatically when the implement is raised into the transport position and bias the locking device in the locked position.
The same device is needed to also permit the operator, having arrived at the field, to engage the operator before getting on to the tractor such that the locking device will unlock when the implement is raised fully so that the operator can commence to use the implement without again dis-mounting from the tractor to unlock the locking device. The device is to also hold the locking device in the unlocked position so that the locking device does not engage when the implement is raised during field operation to clear the cut crop or an obstacle.